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Facilitating electric-propulsion of autonomous vehicles through efficient design of a charging-facility network
Get PDFAdult Children\u27s Education and Mothers\u27 Health: Exploring the Roles of Adult Children\u27s Problems and Mothers\u27 Widowhood Status
No full textEducation provides people with material, social, and cognitive resources which can bolster wellbeing, and a growing body of literature documents a positive association between adult children’s education and older parents’ health. Although researchers have begun to explore mechanisms which underlie and shape this association, few studies have considered the role of family context. Guided by the social foreground perspective, the central aims of this dissertation are to investigate: (1) whether adult children’s problems account for the relationship between adult children’s education and mothers’ depression and (2) whether the size of the association between adult children’s education and mothers’ depression varies between married and widowed mothers. To answer these questions, I utilize mediation and moderation techniques and data collected as part of the Within-Family Differences Study. Consistent with past work, I found that mothers with children who completed more education reported fewer depressive symptoms. In the first substantive chapter, mediation analyses suggested that this relationship was mediated by the proportion of adult children who have experienced physical and emotional problems in the last five years. Consistent with the life course perspective and cumulative inequality theory, these results highlight the ways in which (dis)advantages that impact health accumulate both across age and across generations. In the second substantive chapter, moderation analyses revealed that the association between adult children’s education and mothers’ psychological well-being was weaker among widowed mothers. I innovatively argue that these results are consistent with principles of socioemotional selectivity theory. Taken together, the results from these two chapters illuminate the importance of considering family context when studying the intergenerational implications of education for health. In addition, by augmenting our understanding of how and under what conditions adult children’s education matters for mothers’ psychological well-being, my results offer important insights for stakeholders invested in improving the psychological well-being of older adults
Usability Evaluation of a Community Pharmacy Health Information Exchange Interface Prototype
Get PDFObjectiveFew community pharmacies have access to health information exchange (HIE) data. We conducted a first-of-its-kind usability evaluation of an HIE interface prototype (referred to throughout as the “HIE-Pioneer mock-up”) developed with pharmacists and pharmacy technicians to aid future implementation in community pharmacies.
MethodsCommunity pharmacists and pharmacy technicians were recruited to complete usability evaluations with the HIE-Pioneer mock-up. Each usability evaluation lasted up to 60 minutes. System usability scale (SUS) scores were collected from each participant following each usability evaluation session and summarized with descriptive statistics. Usability evaluation videos were reviewed for common usability attributes, such as the impact of identified usability problems, learnability, and efficiency. Time on task, task success rates, and prototype utilization were also recorded.
ResultsSixteen total participants completed usability testing across three community pharmacies. The average SUS score was 69.7 (scale 0–100, where 100 is the best), with pharmacists on average reporting higher satisfaction than technicians (74.1 vs. 65.3, respectively). Altogether, we identified 23 distinct usability problems. Key problems identified included needed clarification in tool label names and accessibility of HIE links within the existing workflow. Overall, the usability of the HIE-Pioneer mock-up generally fostered pharmacy professionals\u27 ease of learning and efficiency.
ConclusionOur study identified key areas, and potential solutions, to improve the usability of the HIE-Pioneer mock-up. Overall, pharmacy professionals viewed the HIE-Pioneer mock-up positively, with good satisfaction ratings. The HIE-Pioneer mock-up provides a blueprint for future HIE implementation in community pharmacy settings, which would increase community pharmacy teams\u27 access to HIE data nationwide. Community pharmacy access to bi-directional HIE is expected to improve communication among more health care professionals involved in patient care and equip pharmacy professionals with needed information for improved clinical decision-making
Holistic energy landscape management in 2D/3D heterojunction via molecular engineering for efficient perovskite solar cells
Get PDFConstructing two-dimensional (2D) perovskite atop of 3D with energy landscape management is still a challenge in perovskite photovoltaics. Here, we report a strategy through designing a series of π-conjugated organic cations to construct stable 2D perovskites and to realize delicate energy level tunability at 2D/3D heterojunctions. As a result, the hole transfer energy barriers can be reduced both at heterojunctions and within 2D structures, and the preferable work function shift reduces charge accumulation at interface. Leveraging these insights and also benefitted from the superior interface contact between conjugated cations and poly(triarylamine) (PTAA) hole transporting layer, a solar cell with power conversion efficiency of 24.6% has been achieved, which is the highest among PTAA-based n-i-p devices to the best of our knowledge. The devices exhibit greatly enhanced stability and reproducibility. This approach is generic to several hole transporting materials, offering opportunities to realize high efficiency without using the unstable Spiro-OMeTAD
Electric Field-Assisted Nanofiltration for PFOA Removal with Exceptional Flux, Selectivity, and Destruction
Get PDFPer- and polyfluoroalkyl substances (PFAS) pose significant environmental and human health risks and thus require solutions for their removal and destruction. However, PFAS cannot be destroyed by widely used removal processes like nanofiltration (NF). A few scarcely implemented advanced oxidation processes can degrade PFAS. In this study, we apply an electric field to a membrane system by placing a nanofiltration membrane between reactive electrodes in a crossflow configuration. The performance of perfluorooctanoic acid (PFOA) rejection, water flux, and energy consumption were evaluated. The reactive and robust SnO2–Sb porous anode was created via a sintering and sol–gel process. The characterization and analysis techniques included field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), ion chromatography, mass spectroscopy, porosimeter, and pH meter. The PFOA rejection increased from 45% (0 V) to 97% (30 V) when the electric field and filtration were in the same direction, while rejection capabilities worsened in opposite directions. With saline solutions (1 mM Na2SO4) present, the induced electro-oxidation process could effectively mineralize PFOA, although this led to unstable removal and water fluxes. The design achieved an exceptional performance in the nonsaline feed of 97% PFOA rejection and water flux of 68.4 L/m2 hr while requiring only 7.31 × 10–5 kWh/m3/order of electrical energy. The approach’s success is attributed to the proximity of the electrodes and membrane, which causes a stronger electric field, weakened concentration polarization, and reduced mass transfer distances of PFOA near the membrane. The proposed electric field-assisted nanofiltration design provides a practical membrane separation method for PFAS removal from water
Modeling and Experimental Validation of a Resilient Extraterrestrial Habitat Interior Environment
No full textThe NASA-funded Resilient Extra-Terrestrial Habitat Institute (RETHi) aims at developing the necessary fundamental knowledge to enable the design of future resilient deep space habitats. To achieve this, RETHi has developed a Modular Coupled Virtual Testbed (MCVT) consisting of various subsystems (such as power, structural, ECLSS, etc.) to simulate a range of deep space hazardous scenarios and assess the ability of the systems to recover from expected and unexpected fault scenarios under both crewed and uncrewed situations. The physics-based Simulink models within MCVT allow for direct interconnections among components, including damage cascading effects, repairability features, and various failures. Besides the MCVT platform, a Cyber Physical Testbed (CPT) has also been conceptualized to perform real-time experiments with physical portions of the MCVT models (e.g., structural, thermal and pressure management systems). The overarching goal of CPT is to implement and validate decision-making algorithms under various scenarios (e.g., leaks, thermal bridges, etc.), introduce controllable and realistic uncertainties (e.g., communication delays, sensing faults, etc.), and assess resilience, control effectiveness and autonomy. The CPT design consists of three main physical systems: the inflatable bladder, the aluminum dome structure, and the thermal transfer panels connected to a low-temperature chiller. Pressure and temperature controls inside the bladder are achieved by means of a pressure regulator and a mini-split heat pump system, respectively.One of the core aspects of both MCVT and CPT is the habitat interior environment which includes the coupled temperature and pressure effects due to interior and exterior loads as well as the necessary conditions to ensure the crew survival.As part of this work, a dynamic Habitat Interior Environment Model (HIEM) has been developed to simulate the behavior of a two-zone habitat in real-time. The model can directly interact with other subsystems such as the ECLSS and structural protective layer (SPL) and features various disturbances including pressure leaks due to meteorite impacts or airlock failures. The HIEM has been further extended to also include various fire intensity scenarios and also to enable the isolation of the zones by means of a door in case of an emergency or simply due to the architecture of the future habitat.The CPT system is utilized to test the capability of HIEM in predicting the behavior of the interior environment in various scenarios. To impose the necessary thermal loads to the habitat structure (i.e., aluminum skeleton and inflatable bladder) in the laboratory environment, thermal transfer panels with coiled copper piping and aluminum heat spreaders have been designed to provide uniform temperature distributions. A cryogenic chiller with Syltherm as the working fluid is used to maintain and provide the necessary operating range between -40 °C and 60 °C.The HIEM was modified to describe the physical sizing of the bladder as well as to capture the heat transfer characteristics between the bladder, the aluminum structure, and thermal transfer panels. In addition, the models also included the effects of air infiltrations within the bladder, various sources of heat losses by conduction and convection, and thermal resistances associated with non-perfect contacts between bladder and transfer panels. Experimental data was used to validate the model predictions and different operating conditions as well as to improve the model accuracy by identifying key thermal resistances and capacitances
Practical Methods for Fuzzing Real-World Systems
No full textThe current software ecosystem is exceptionally complex. A key defining feature of this complexity is the vast input space that software applications must process. This feature inhibits fuzzing (an effective automated testing methodology) in uncovering deep bugs (i.e., bugs with complex preconditions). We improve the bug-finding capabilities of fuzzers by reducing the input space that they have to explore. Our techniques incorporate domain knowledge from the software under test. In this dissertation, we research how to incorporate domain knowledge in different scenarios across a variety of software domains and test objectives to perform deep bug discovery.We start by focusing on language interpreters that form the backend of our web ecosystem. Uncovering deep bugs in these interpreters requires synthesizing inputs that perform a diverse set of semantic actions. To tackle this issue, we present Gramatron, a fuzzer that employs grammar automatons to speed up bug discovery. Then, we explore firmwares belonging to the rapidly growing IoT ecosystem which generally lack thorough testing. FirmFuzz infers the appropriate runtime state required to trigger vulnerabilities in these firmwares using the domain knowledge encoded in the user-facing network applications. Additionally, we showcase how our proposed strategy to incorporate domain knowledge is beneficial under alternative testing scenarios where a developer analyzes specific code locations, e.g., for patch testing. SieveFuzz leverages knowledge of targeted code locations to prohibit exploration of code regions and correspondingly parts of the input space that are irrelevant to reaching the target location. Finally, we move beyond the realm of memory-safety vulnerabilities and present how domain knowledge can be useful in uncovering logical bugs, specifically deserialization vulnerabilities in Java-based applications with Crystallizer. Crystallizer uses a hybrid analysis methodology to first infer an over-approximate set of possible payloads through static analysis (to constrain the search space). Then, it uses dynamic analysis to instantiate concrete payloads as a proof-of-concept of a deserialization vulnerability.Throughout these four diverse areas we thoroughly demonstrate how incorporating domain knowledge can massively improve bug finding capabilities. Our research has developed tooling that not only outperforms the existing state-of-the-art in terms of efficient bug discovery (with speeds up to 117% faster), but has also uncovered 18 previously unknown bugs, with five CVEs assigned
Influence of Irrigation and Drainage Practices on Water Resources
No full textClimate change, increasing demand and overuse have resulted in water stress, a condition where available water resources are not enough to meet needs, in many parts of the US. At the same time, increasing seasonal precipitation, and more intensive management practices mean subsurface drainage is expanding in the Midwest, which has resulted in significant nutrient loading to water bodies and changes to the hydrologic balance of river basins. To ensure the sustainability of water resources, it is crucial to understand how much water available, and how agricultural water use is impacted by changing weather, stress and legal conditions. Water use systems must be properly managed to ensure prosperous agricultural production, and secure water resources. The overall goal of this research is to evaluate the sustainability of groundwater resources in the US through better quantification of surface and groundwater use and the interactions with agricultural water management practices.Watershed-scale measures of surface water and groundwater stress were calculated to explore the spatial and temporal variability of water stress in the US. Much of the Western US, which has been in a water stress situation for 35 years (1985-2015), is shifting to increasing surface water use, but both groundwater stress and surface water stress are continuing to rise. An increase in groundwater stress has also been observed in isolated watersheds in the eastern United States. The pattern of rising surface water stress corresponds more closely to changes in water use, whereas the pattern of rising groundwater stress corresponds to changes in water supply. It has been observed that those watersheds that experienced water stress in 1985 have responded by increasing their water withdrawals from other sources, but they have not decreased their agricultural water withdrawals.The decision to invest in groundwater irrigation depends on physical water availability and cost, as well as the right to use the water, as determined by groundwater doctrines. Overall, groundwater withdrawals for irrigation have increased in humid and temperate regions, and irrigation per unit area has also increased across the US. At the same time, the fraction of irrigation coming from groundwater is growing, suggesting a potential shift in the preferred water source. This is especially true in states following absolute ownership, correlative rights, and reasonable use doctrine. Correlative Rights doctrine prevalent in the western Corn Belt and Absolute Ownership doctrine (Indiana) appears to encourage increasing groundwater withdrawals during times of stress. These states increase their irrigation rate and the fraction of groundwater withdrawals for irrigation when less surface water is available.Subsurface drainage is common practice across vast areas of the US’ Corn Belt. Subsurface drainage can provide a better growing environment for crops, removing the excess water from the root zone and improving the trafficability of the soil. However, by lowering the water table, drainage has the potential to reduce groundwater recharge. Controlled drainage allows the user to control the water table by adjusting the height of the outlet to limit the subsurface flow during the non-growing season